Kelly McGonigal, Stanford University health psychologist and author of The Willpower Instinct, posits that people who are having a tough time sticking to their resolutions aren't experiencing difficulty because their goals are flawed. Merely that it takes a lot of willpower to stick to long-term goals. This is particularly tough when we (and our entire culture) value the gratification of short-term desires. It's always a struggle between giving in to the "future self" versus the "immediate self."

TIP: Keep your "future self" in mind. Remember the kids put to the marshmallow test? If you can decide against instant gratification and tolerate temporary discomfort, you will be more fully able to stick to resolutions that have long-term benefits.

2. Remove yourself from situations of temptation

And speaking of the marshmallow test... original researcher Walter Mischel figured out that the children who were successfully able to delay gratification weren't wired any differently from the unsuccessful kids. They simply adopted a better strategy, something Mischel dubbed the “strategic allocation of attention.” The kids stayed under the table, or covered their eyes, or tied and retied shoelaces — any activity to get their minds off the marshmallow or to obscure it from their view.

TIP: To resist the temptation of your own personal "marshmallow," you have to remove yourself from its presence, or from situations which trigger you wanting it.

3. Stick with it for at least 66 days

Roy Baumeister's book Willpower: Rediscovering the Greatest Human Strength suggests concentrating on only one goal at a time. Baumeister explains that willpower is like a muscle that we can exhaust, so you have to concentrate on one goal at a time for success.

But alongside this, every resolution boils down to reprogramming your mind to adopt a new habit. And researchers say that new habits require an average of 66 days (or a little over two months) to fully form. In fact if the behavior is particularly complex, it may take up to eight months!

TIP: Don't throw in the towel after just a week. Give your new habit an actual chance to make a change in your life.

4. Limit the amount of stuff you're memorizing

In an experiment led by Baba Shiv at Stanford University, two groups were tasked with memorizing a number. One group was given two digits, and a second group was given seven digits. Then they had to decide between eating a slice of chocolate cake or a bowl of fruit salad.

The students who had to memorize the seven-digit number were nearly twice as likely to choose the cake as students given two digits. It's a concept called cognitive load — the idea that the total amount of mental effort (the need to memorize extra numbers, for example) saps our ability to do other things, such as resist high calorie desserts or stick to resolutions.

TIP: Instead of keeping stuff in your brain, unload your ideas and to-do items into a trusted organizational system that you can refer to anytime you need. It's a fundamental principle of David Allen's Getting Things Done (GTD) productivity method.

What makes your New Year's resolutions worthwhile?

What advice do you have for sticking to your resolutions? Hit the comments and help us out by letting us know what keeps you in line after the new year!